Field of the Invention
Dial-up telecommunication services have been principally concerned with providing low bandwidth circuits between subscribers that are capable of carrying speech. Non dial-up telecommunications services have been provided as permanent private circuits at various bandwidths. Many of these private circuits consist of digital bit streams. Because the data carried by many of these digital private circuits is supplied by the customer, the operator of the telecommunication service does not have any control over the data transported and therefore may have no opportunity for routinely inserting known data formats in order to ensure that the bit streams are being correctly transported.
Although new multiplexing techniques often carry extra data in order to enable suitable performance measuring to be performed; these multiplexing techniques are often not suitable on certain parts of networks and in particular on the access interfaces to the subscriber's premises.
The introduction of digital dial-up services enables methods to be employed in telecommunication access networks to ensure the satisfactory performance monitoring of the digital circuits.